Article in The Bulletin of Legal Medicine · December 014 doi: 10. 17986/blm. 2014193853 citation reads 13,105 authors: Some of the authors of this publication are also working on these related projects

Investigative psychology
Investigative psychology utilizes data obtained from 
various offender groups from different cultures. 
Furthermore, differentiation in types of offenders makes 
it possible to evaluate each case separately and apply the 
general patterns drawn from the actuarial data. David 
Canter, a British psychologist, is the pioneer of 
Investigative psychology, started with the goal of 
transforming 'criminal profiling' from intuitive and 
strongly experience based inferences to a more 
scientifically based theory generation.
One main objective is to study the similarities and 
differences within/between offender groups, creating 
patterns and applying these patterns to individual cases.
IP can be briefly summarized as: (6) The scientific 
discipline concerned with the psychological principles, 
theories and empirical findings that may be applied to 
investigations and the legal process The focus is on the 
ways in which criminal activities may be examined and 
understood in order for the detection of crime to be 
effective and for legal proceedings to be appropriate. As 
such, Investigative Psychology is concerned with 
psychological input to the full range of issues that relate to 
the management, investigation and prosecution of crime.
Canter presented 5 important questions to focus on 
during the analysis of a specific crime (3). The main 
inference questions that need to be asked with the 
objective of improving criminal and civil investigations 
are: 

Linking – which crimes are the same offender?

Salience – what distinguishes the offender?

Characteristics – How might we identify him?

Location – where might he be based?

Prediction – what might he do next?
A >C Equations 
Cilt 19, Sayı 3, 2014
Fig 1. The action-characteristics (A C) eguation, a model of 
what is involved in ''profiling'' an unkown offender.Inference 
must be made about offender from information abouthow the 
crime was committed,inlcudingits location, time, and the victim 
details. To make such inferences, appropriate psychological 
theories and models must be drawn upon.

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Adli Tıp Bülteni
One important role of psychology in criminal 
investigations is to define the relationship between 
offender's behaviors and his/her characteristics which 
will assist the investigators where and what type of person 
to look for (8, 3). Whilst deriving inferences, every 
available information related to a crime, including 
witness/victim accounts, crime scene evidence, 
offender's actions during the offence, his/her interaction 
with the crime setting has to be evaluated under the light 
of psychological principles (7). 
When there is no physical evidence gathered from the 
crime scene or any witness/victim accounts regarding the 
perpetrator's identity, a thorough analysis of certain 
details of the crime in terms of the “psychological traces” 
left by the perpetrator is the only way to reach inferences 
about the characteristics of the offender.
Profiling equations proposed by Canter (8) “capture 
the scientific perspective for inferring associations 
between the actions that occur during the offence – 
including when and where they happen and to whom-and 
the characteristics of the offender, including the 
offender's criminal history, background, base location, 
and the relationships to others” (1).
These equations aim to form consistent relationships 
between A and C with the application of psychological 
theories. There is no one-to-one relationship between 
Actions (A) and Characteristics (C). Instead, the 
relationship between A and C is canonical which refers to 
the high number of possible associations between 
different sets of actions and mixture of characteristics 
under different circumstances (1). The same action can be 
indicative of different characteristics based on the context 
and/or the criminal background of the perpetrator. For 
instance, using an accelerant in an arson can imply an 
above average IQ in a young arsonist but the same action 
will not indicate the same characteristic in an experienced 
arsonist. Also, different actions can indicate the same 
characteristic. For example, having a burglary related 
conviction can be seen both in rapists and robbers (3).
In the A>C equation, the characteristics are inferred 
from the actions during the offence by applying a theory 
or argument based on scientific evidence. In order to 
achieve a scientific way of identifying the relationships 
between actions and characteristics, a theoretical 
framework has to be formed based on research findings 
(5, 1). 
Various factors contributing to variations in criminal 
behavior such as personality, modes of interpersonal 
interactions, socio-economic factors etc. should be 
subject to careful examination. 
Canter presented the profiling equation as (3):
“F1A1 +………+ FnAn = F1C1+……..+FnCm”
In this equation the most prominent component is the 
F which refers to the values of weightings which are the 
'functions' (F) in the relationship between As and Cs. 
The theoretical framework for drawing inferences is 
based on certain principles.